Jeff's Lunchbreak

Biplane, in practical application, more aerodynamically advanced than monoplane. However Jeff Lunchbreak is also correct in his observation that biplanes are usually build with shorter wing span, compare to monoplane, so the aerodynamic advantage of biplane is reduced by increased induced drag. "In the work by Prandtl [published in 1922] it is proved that the induced resistance of a biplane is smaller than that of
a reference monoplane, or equivalent monoplane, namely having the same wing opening and the same resultant lift force of the multiplane and with an elliptic lift distribution."
Jeff Lunchbreak uses incorrect criteria for comparison of biplane and monoplane. The correct comparison would be the comparison of the cost for transporting a given payload (a 200 lbs passenger) from point A to point B. With the same wing span airplanes the cost of such transportation work will be less on biplane because of reduction of the induced drag. Each wing of biplane would have 2 times higher aspect ratio compare to the same wing span and the same lift monoplane. Because the biplane wing will be more efficient it will require less of wing area in order to do the same transportation job. It is an incorrect observation that older biplanes were less aerodynamically advanced compare to older monoplanes. In fact, the first Americal airplane that took off the grounds in Outer Banks, NC in 1903 was a biplane. Biplane’s aerodynamic advantage allowed brother’s Wright to take off with very low motor power. Monoplanes have become common when more powerful engines came to the market. Monoplane is also less expensive in mass production. The World War II required many low cost airplanes, and it development of biplanes stopped for decades. Modern airspace designers are looking back to the advantages of biplane aerodynamics versus monoplanes because of increase of fuel cost and increased competition on air transportation market. In practice biplane concept can reduce the cost of air transportation for about 20% compare to monoplane.

Soviet Union has developed a product line of dual rotor Kamov helicopters. Kamov helicopter is about 20% more aerodynamically efficient compare to the same rotor diameter (wing span) single rotor helicopter. Under influence of Soviet sucsess in dual rotor (biplane) helicopters Sikorsky today is taking advantage of dual rotor (biplane) in its new X2 helicopter concept.

triple tandem wings need bi plane and cannard technology so the 130 degree nose rule of high stress modulus activity isnt violated